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The application of linear optimal control theory to the design of active automotive suspensions / Nadjib Louam 

Public ISBD Titre : The application of linear optimal control theory to the design of active automotive suspensions Type de document : texte imprimé Auteurs : Nadjib Louam, Auteur ; D. A. Wilson, Directeur de thèse ; R. Sharp, Directeur de thèse Editeur : University of Leeds Année de publication : 1990 Importance : 161 f. Présentation : ill. Format : 27 cm. Note générale : Thèse de Doctorat : Electronique : Angleterre, University of Leeds: 1990 Bibliogr. f. 162 - 165 . Annexe: [20] f Langues : Anglais (eng) Mots-clés : Linear  optimal  control  theory Suspension  systems Automobiles Half-car  model  problem Correlation Optimal  control Discrete  regulator  framework Computer  simulation Index. décimale : D001690 Résumé : In the present work, linear optimal control theory is applied to the design of active supension systems for automobiles. Most of the effort is directed towards the case of the half-car model problem in which the correlation between front and rear wheel inputs is taken into consideration. Particular attention is focussed on the difference between the optimal correlated and uncorrelated cases. To this end, rigorous mathematical developments are considered. An optimal control law for a vehicle suspension is developed using a discrete regulator framework. The time delay between the disturbance due to the road at the leading and trailing wheels is incorporated, without approximation, into the model. The control law derived for the optimal correlated problem requires information gathered at the leading wheel. The superiority of this solution over the suboptimal one, which does not incorporate leading wheel information, is clearly confirmed by the computer simulation. To enhance the performance of active suspension systems, under preview of the road, the application of linear optimal control theory is also considered. The vehicle model with completely général inputs to front and rear wheels is set up as an optimization problem and it is converted to standard form by a state variable transformation. It is shown that the solution for the optimal tracking problem over a finite time interval is not of practical use, because it requires knowledge of the road surface over the whole journey time, whereas for a preview control scheme, a sensor mounted on a car in motion would provide a continuously moving window of road surface data. By combining linear optimal theory with ideas for the overtaking optimality method, control laws for both infinite and finite preview problems are produced. The solution obtained in this framework utilizes road surface data in precisely the format which would be available from a preview sensor. The discrete time version of this solution is also examined. In the absence of limitations on either processing or actuator speeds, the value of preview in enhancing quarter and half-car suspension performances is assessed as a function of preview time and the simulation results show clear benefits are possible when the future road information is included. The application of linear optimal control theory to the design of active automotive suspensions [texte imprimé] / Nadjib Louam, Auteur ; D. A. Wilson, Directeur de thèse ; R. Sharp, Directeur de thèse . - [S.l.] : University of Leeds, 1990 . - 161 f. : ill. ; 27 cm. Thèse de Doctorat : Electronique : Angleterre, University of Leeds: 1990 Bibliogr. f. 162 - 165 . Annexe: [20] f Langues : Anglais (eng) Mots-clés : Linear  optimal  control  theory Suspension  systems Automobiles Half-car  model  problem Correlation Optimal  control Discrete  regulator  framework Computer  simulation Index. décimale : D001690 Résumé : In the present work, linear optimal control theory is applied to the design of active supension systems for automobiles. Most of the effort is directed towards the case of the half-car model problem in which the correlation between front and rear wheel inputs is taken into consideration. Particular attention is focussed on the difference between the optimal correlated and uncorrelated cases. To this end, rigorous mathematical developments are considered. An optimal control law for a vehicle suspension is developed using a discrete regulator framework. The time delay between the disturbance due to the road at the leading and trailing wheels is incorporated, without approximation, into the model. The control law derived for the optimal correlated problem requires information gathered at the leading wheel. The superiority of this solution over the suboptimal one, which does not incorporate leading wheel information, is clearly confirmed by the computer simulation. To enhance the performance of active suspension systems, under preview of the road, the application of linear optimal control theory is also considered. The vehicle model with completely général inputs to front and rear wheels is set up as an optimization problem and it is converted to standard form by a state variable transformation. It is shown that the solution for the optimal tracking problem over a finite time interval is not of practical use, because it requires knowledge of the road surface over the whole journey time, whereas for a preview control scheme, a sensor mounted on a car in motion would provide a continuously moving window of road surface data. By combining linear optimal theory with ideas for the overtaking optimality method, control laws for both infinite and finite preview problems are produced. The solution obtained in this framework utilizes road surface data in precisely the format which would be available from a preview sensor. The discrete time version of this solution is also examined. In the absence of limitations on either processing or actuator speeds, the value of preview in enhancing quarter and half-car suspension performances is assessed as a function of preview time and the simulation results show clear benefits are possible when the future road information is included.

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